Tips on Roasting Veggies

Virginia posted what looks to be a fabulous recipe on Roasted Tomato
Sauce that I can't wait to try. Thanks Virginia.
Her comment at the end was:
We cooked this in a (deeper and smaller) lasagna pan for almost four
hours. It still had not cooked down to the quantity Thomas suggests,
but it smelled so good we had to eat it! Yum!!
I have learned through experimenation that the best pan to roast
veggies in is a flat cookie sheet. If the pan has sides any higher,
the moisture does not evaporate and it is hard to get that roasted look
and feel.
I also roast at much higher temperatures for a shorter period of time
(450 degrees for 30 minutes?), which might be interesting for this
recipe.
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